This invention relates to a method for producing an injection-molded card with a decorative layer, in particular a credit card, check card, bank card, ID card, telephone card and the like, according to the preamble of claim 1, and to an injection-molded card produced by said method.
A number of methods are known for providing an injection-molded card with a decorative layer. An especially simple method is to apply the decorative layer by printing technology to a card blank produced by injection molding. One disadvantage of this procedure, however, is that single cards are printed, which is relatively elaborate and expensive. Further, it is very difficult to produce a high-quality, i.e. for example high-gloss, card surface with this technique. A further disadvantage is that the decorative layer is applied as the outermost layer and can thus be damaged relatively easily. This can be prevented for example by covering the card with transparent lacquer, but this makes the method even more expensive.
The method known from EP 0 350 179 B1 largely eliminates the stated disadvantages. According to this method the decorative layer is applied to the card body in the form of printed labels. In this method the card can be provided with a decorative layer on both sides by inserting two labels into a mold in such a way that the labels lie against the inner sides of the mold, the printed sides of the labels facing inwardly. Subsequently a reaction-injection-moldable plastic material is injected between the labels. After the plastic material hardens one can remove the finished card bearing the labels on its two main faces from the mold.
However, the method described in EP 0 350 179 B1 can only be used in conjunction with reaction-injection-moldable plastic material, whereby the pressures and temperatures that occur are considerably below the values of conventional injection molding methods. This means that the spectrum of usable materials is restricted to a few reaction-injection-moldable plastics. If one used the card labels known from EP 0 350 179 B1with conventional injection molding technology, the decoration applied by printing technology would be damaged during the injection molding process as a result of the high temperatures and pressures that occur.
The invention is therefore based on the problem of stating a method for producing an injection-molded card with a high-quality decorative layer and an accordingly produced injection-molded card.
This problem is solved by the characterizing features of the present invention. Advantageous embodiments of the present invention further improve over known methods.
According to a preferred embodiment of the invention, at least one carrier layer provided with a decorative layer is introduced into the injection mold. To protect the printed image from damage by the injected injection molding material, the printed image is covered with a protective layer which prevents direct contact between the printed image and the injection molding material. For this purpose the carrier layer is inserted into the injection mold in such a way that the protective layer does not lie against the wall of the injection mold, i.e. the injection molding material is injected against the printed side of the carrier layer. This makes it possible to produce high-quality labels simply, for example by sheet printing, and provide them with a protective layer and subsequently process them into high-quality cards using conventional injection molding. The inventive method thus has the advantage of using efficient and cost-effective standard techniques while nevertheless producing a very high-quality product.
The inventive method makes it possible to provide the card with a high-quality decoration on one or both sides without great additional expense and without having to accept a restricted choice of injection-moldable plastics or restricted choice of inks for the decoration. The protective layer also makes it possible to incorporate photos, holograms, etc., as a decorative layer.
According to an advantageous embodiment of the invention, the protective layer is made of a material which increases the adhesion of the label to the injection-molded body. This attains an additional improvement in the durability of the card.
Further, the protective layer can also be provided with pigments or dyes in order to provide a uniform, colored background for the printed image for example. This also makes it possible to produce inscription properties, such as laserings, or to graphically design the protective layer itself, for example by producing dulling effects, logos, writing or the like by blind embossings.
Finally, it is also possible to incorporate feature substances in the protective layer which can be used in connection with the authenticity testing of the card. Security features incorporated in the card in this way are comparatively hard to forge since they are not disposed directly on the surface.
In particular with chip cards or similar cards it is advantageous to provide the coated foil with a gap into which a dummy having the shape of a later incorporated IC module is inserted during injection molding.
A further advantageous development of the inventive method provides that the carrier layer consists of a transparent foil. This foil is placed with the uncoated main face against the wall of the injection mold. The decoration and the protective layer are thus directed inwardly within the injection mold. The protective layer prevents the decoration from being impaired by the injection molding process.
If a transparent injection molding material is used, the decoration can also be printed on one or both sides of an inside layer of the card. The printed inlay is in this case also provided with a protective layer which protects the decoration from high temperatures and pressures and high mechanical stress during injection molding.